A simple method for scanning individuals for concealed metal objects exists by using metal detectors. A simple device does not exist for detecting concealed nonmetallic objects. Nonmetallic or dielectric objects can be uses in dangerous or threatening ways, or contain dangerous or harmful materials such as explosives. Thus there is a need to detect these objects.
Recently, the U.S. Department of Transportation Safety evaluated backscattered X-ray technology for this purpose. Although effective at imaging objects concealed under the clothing, it still uses potentially harmful X-rays, and the machines are expensive and bulky.
What is needed is a simple scanner for detecting dielectric objects that operates like a hand-held metal detector or the walk-through panel that warn security officers when concealed plastics are probable.
Over the last few years, a growing number of accidents occurred during the fueling of automobiles. Devastating fires or explosions occurred due to static electricity buildup on the individuals that pumped the fuel. At the instant of touching the fuel pump, a spark from the static electricity ignited the fumes and consequently the fuel being pumped. These accidents may have been avoided if a static electricity build up warning device existed. For example, a warning device might be mounted on the pump console or pump handle that indicates if static buildup on the approaching individual is detected. The warning would direct the individual to discharge the static electricity on the car chassis or other safe location before even touching the pump. Thus, a need exists for a warning device that monitors the electrostatic charge on an individual while in proximity to an explosive environment such as a gasoline-fueling pump.
The invention has application of a warning device in electronic assembly areas. Electrostatic fields can destroy electronic components. During assembly, a person may use electrostatic discharge equipment to keep their body at ground potential. The equipment may include shoe and wrist grounding straps. Even with this equipment, if a person picks up a charged object like a piece of plastic, damage to sensitive parts can occur. In this situation, it would be useful to have a warning device.
To address the warning device requirements above, a need exists for a special proximity sensor. It must detect both the presence of an individual and determining whether their body is has static charge. Existing technology does not address both of these measurements simultaneously, because static charge occurs in nature in many locations giving false alarms. This phenomenon creates significant noise to a sensor that detects only charge. For example, if someone at another location shuffles their feet, the movement of static charge between their body and the floor causes noisy signals to appear in a charge detector. The problem is these noisy signals are not distinguishable from the charge on a person closest to the sensor. Thus a single sensor capable of detection only charge is said to have charge-proximity ambiguity.
So what is needed is a method and apparatus for uniquely detecting proximity to a charged object. Additionally, the proximity sensor must be capable of detecting dielectric and charged objects such as plastics concealed by various covering materials.
Computers and games a commonly controlled by plastic stylus or swords, or sticks. The motion or commands are detected by radar, light beams, video cameras or touch controlled screens. What is desired is to simply discern motions of a hand holding a plastic object from a bare hand, or one holding a conductor. The detection of motion of a bare hand or conductor is described in the Motional Command System of U.S. patent application Ser. No. 10/772,908. The addition of the ability to detect plastic or dielectric objects a user's hand offers interesting possibilities for toys, robots, and artificial sensory technologies. To do this what is needed is a sensor to detect a nonconducting dielectric material such as plastic material via charge and proximity measurements.
Medical and imaging technology continually strives to arrive at low cost non-invasive images for diagnostic uses. A sensor with the ability to monitor charge density and proximity within objects offers possibilities for imaging.